&one.relative_identifier(
  &two,
  key: &three
)
&one.relative_identifier(
  &two,
  key: &three
)(
  &four,
  key: &five
)
&one.relative_identifier key: &two
&one.relative_identifier unqualified &two,
                                     key: &three
&one.relative_identifier &two,
                         key: &three